Dairy Wastewater Treatment Using Horizontal Subsurface Flow Constructed Wetland Planted with Tyhpa Iatifolia and Scirpus Lacustris
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Date
2013-03
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Addis Ababauniversity
Abstract
Environmental pollution resulting from the discharge of untreated industrial effluents has been
putting serious risks on the survivability and perpetuation of all living things including human
beings for the past few years. From the various treatment methods natural means of treating
industrial wastewater have been exercised in many parts of the world for they are
environmentally permissible and help to keep its natural values. Among those natural ways of
treating wastewater constructed wetlands have been utilized for the past few decades. In this
research three horizontal subsurface flow constructed wetlands (HSSFCWs) have been used for
the treatment of dairy wastewater discharged from Ada milk factory. The first HSSFCW was kept
as control with only gravel and the rest two HSSFCWs were planted with widely used emergent
plant species, Typha latifolia and Scirpus lacustris. The wetlands flow rate was adjusted to 25
L/d and as hydraulic retention time (HRT) 8 days was used for three replicates of the
experiments. After laboratory investigations were carried out it was found that the wetland
planted with Scirpus lacustris showed better capacity in removing pollutants from the dairy
wastewater than the wetland planted with Typha latifolia. The average removal efficiencies of
the wetland planted with Scirpus lacustris and the unplanted wetland were found as follows,
respectively. BOD (84.2%, 65.2%), COD (84.4%, 68.2%), TN (43.4%, 22.8%), NH4+-N (84.2%,
59.2%), NO3_N (97.5%,88.7%), TSS (65%,70%,),VSS(32%,43%), TP (53.8%,27%), OP
(80.7%,75.2%), FOG (95.3%,93%), TCa (39%,21.8%) and TC (89.7%,69.3%). Besides their
importance in wastewater treatment, these emergent plants have versatile uses among these their
medicinal and dietary values were widely recorded. Thus, it is environmentally advisable
mechanism to utilize constructed wetlands for wastewater treatment. From laboratory
investigations it was found that BOD, TN, NH4+-N, NO3--N, TP and PO43--P are the main factors
for the pollution of the Dairy wastewater.
Keywords: Constructed wetland, Scirpuslacustris, Typhalatifolia, dairy wastewater
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Keywords
Constructed wetland, Scirpuslacustri, Typhalatifolia, dairy wastewater